Human brain high-resolution OGSE diffusion MRI with slice-by-slice B0 shimming in an ultra-high performance gradient 3T MRI system

Motivation: Time-dependent diffusion MRI has emerged for tissue microstructure imaging. Multi-shot, or segmented, EPI diffusion acquisition commonly used for reducing image distortion due to B0 field inhomogeneity, may not be applicable due to the prolonged scan time. Goal(s): To propose an optimized B0 shimming algorithm for single-shot EPI acquisition and compare image quality to that using two-shots EPI acquisition. Approach: Dynamic linear slice-by-slice B0 shimming accounting for gradient nonlinearity was implemented in both OGSE and PGSE diffusion MRI. Results: Dynamic shimming reduces B0 field inhomogeneity and image distortion for both OGSE and PGSE, especially for high resolution acquisitions with long echo spacing. Impact: MRI-based tissue microstructure imaging can benefit from the fast, high-quality, time-dependent diffusion MRI with the optimized dynamic linear slice-by-slice B0 shimming technique that is applicable to any MRI system.